Method of making high performance activated aluminum sesquichlorohydrate powders

ABSTRACT

Activated aluminum sesquichlorohydrate (AASCH) powders prepared by (a) diluting the concentrated aluminum sesquichlorohydrate (ASCH) solution to from about 10% to about 25% by weight, (b) heating the diluted solution to obtain a Band III polymer concentration of at least about 20% and a Band IV polymer concentration of at least about 15%, (c) drying the heated solution to powders, and (d) optionally screen or light mill the powders to free flowing spherical particles are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.15/341,453, filed Nov. 2, 2016 which is a continuation of U.S.application Ser. No. 14/755,138, filed Jun. 30, 2015, which is now U.S.Pat. No. 9,572,758, the disclosures of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

The most effective antiperspirant active for an aerosol formulation onthe market today is activated aluminum chlorohydrate (AACH). The AACHpowder has Al:Cl atomic ratio of greater than 1.90 and mostly about 2.0,and has Band III polymer concentration of at least 20% and Band IVpolymer concentration of less than 10%, when analyzed by the sizeexclusion chromatogram (SEC) using a high performance liquidchromatograph (HPLC).

Antiperspirant stick formulations can use the more efficaciousmaterials, such as activated aluminum zirconium salts. However, aerosolspray formulations cannot use the activated aluminum zirconium salts dueto the safety concern of inhalation of zirconium compounds. Therefore,aerosol spray formulations use the active containing Al salts only.

U.S. Pat. No. 4,359,456 to Gosling et al. discloses an improved Alactive material through the process of heating from 2.5% to 8.5% byweight of aluminum concentration to have Band III polymer concentrationof at least 20%. It discloses that the presence of Al polymers of above100 Angstroms is not necessary to provide the high efficacy. Theimproved Al active material, disclosed in Gosling et al., i.e. basicaluminum chloride, has Al:Cl atomic ratio from about 0.5 to about 3.3.However, the salts having the Al:Cl ratio above 2.1 are not consideredto have any antiperspirant properties, and therefore are not classifiedas conventional antiperspirant actives. Moreover, at lower Al:Cl ratioof about 0.5, it would be almost impossible to have at least 20% of BandIII polymers.

U.S. Pat. No. 4,944,933 to Inward discloses a process of making a basicaluminum chloride in a powder form having Al:Cl atomic ratio of from 1.7to 2.2 and having Band III polymer concentration of at least 20%. Theprocess involves dissolving Al metal powder in aluminum chloride to formthe final basic aluminum chloride solution of 7.5% to 13% by weight withreaction time being within 5 hours at 50° C.-105° C. and drying the BACsolution to powder. Even though the active salt prepared according tothe process has high Band III polymer concentration, the Al polymerspecies, however are mostly Al₁₃ species characterized by ²⁷Al NMRhaving chemical shift at 62.5 ppm that provide low antiperspirantefficacy.

U.S. Pat. No. 5,718,876 to Parek et al. discloses basic aluminum halidesand nitrates having enhanced antiperspirant efficacy that are producedby reacting aluminum metal with aluminum halide or nitrate solution attemperature greater than 85° C. with Al/anion ratio of about 1.2-1.8.The active solution has 30-400 of anhydrous weight having less than 20%of Band III polymers. Parek et al. discloses the concentrated Alsesquichlorohydrate solution with low amount of Band III polymers.

U.S. Pat. No. 8,883,129 to Swaile et al. discloses a method of making anactive having enhanced antiperspirant efficacy comprising an Al-onlysalt having a Band III polymer concentration of at least 20% and no morethan 20% of Al monomer. The method includes (a) making an aqueoussolution of an aluminum salt having at least 20% of Band III polymers,(b) adding an aqueous solution of a monomeric aluminum salt to solution(a), and (c) rapidly drying the mixture to form a product. By minimizingthe contact time between (a) and (b), Swalie et al. will maintain themonomeric state and acidity of the monomeric aluminum salt. The contacttime varies from 1 second to 30 minutes depending on the temperature.Long contact time allows the monomeric aluminum salt to be neutralizedby the aluminum hydroxychloride to form aluminum dimers, trimers andpolymers. However, addition of very acidic aluminum chloride to dilutedand activated aluminum solution will produce free acid upon spray dryingthat will not only corrode the spray dryer, but also cause the formationof colored specks, such as in black, brown, yellow and green colors. Itwill also generate the hygroscopic powder that is difficult toformulate. Specifically, if the active salt of Swaile et al. isformulated into an aerosol, the acidic and hygroscopic powder cancorrode the orifice nozzle of the aerosol spray can, and also formlarger agglomerates, clogging the orifice and preventing the spray fromcoming out of the aerosol can.

US patent application 2006/0104918 to Brown et al. discloses asuspension aerosol composition comprising milled AACH and a masking oilhaving reduced levels of white deposits. However, the very fineparticles generated by milling process may pose health hazard forinhalation when used in an aerosol formulation.

Therefore, there is a need for a new and improved Al active materialwith enhanced antiperspirant efficacy for aerosol application, which isnot too acidic and not too highly hygroscopic and/or does not posesafety concerns of inhalation of hazardous material.

BRIEF SUMMARY OF THE INVENTION

Described herein are activated aluminum sesquichlorohydrate (AASCH) withenhanced efficacy for aerosol application and method of making same.

In one embodiment, method of preparing an activated aluminumsesquichlorohydrate (AASCH) comprises (a) diluting the concentratedaluminum sesquichlorohydrate (ASCH) solution to about 10%-25% by weight,(b) heating the diluted solution to obtain a Band III polymerconcentration of at least 20% and a Band IV polymer concentration of atleast 15%, and (c) drying the solution to form a powder having Al:Clratio of about 1.60 to about 1.90. In another embodiment, the methodfurther comprises (d) screening or light milling the powders to freeflowing spherical particles having a particle distribution profilesuitable for aerosol application.

In one embodiment, the diluted solution is heated until a Band IIIpolymer concentration reaches above about 30%, and preferably aboveabout 40%. In another embodiment, the diluted solution is heated until aBand IV polymer concentration reaches above about 20%, about preferablyabove about 30%. In another embodiment the diluted solution is heated toobtain a combined Band III and Band IV polymer concentration of at leastabout 40%, preferably at least about 50%.

In one embodiment, the drying is done via spray drying.

In one embodiment, the activated aluminum sesquichlorohydrate (AASCH)powders in accordance with the present invention have Al:Cl atomic ratioof from about 1.60 to about 1.90 and has a Band III polymerconcentration of at least about 20% and a Band IV polymer concentrationof at least about 15%. In one embodiment, the activated aluminumsesquichlorohydrate (AASCH) powders have at least about 50% of Band IIIpolymer and Band IV polymer combined. In another embodiment, the AASCHpowder has less than about 1% Band I polymer concentration. In yetanother embodiment, the AASCH powders have no Band I polymer.

In yet another embodiment, the activated aluminum sesquichlorohydrate(AASCH) powder in accordance with the present invention has a Al speciesdistribution that includes at least about 5% of Al₃₀, preferably atleast about 10% of Al₃₀, more preferably at least about 15% of Al₃₀. Inanother embodiment, the activated aluminum sesquichlorohydrate (AASCH)powder in accordance with the present invention has an Al speciesdistribution that includes less than about 10% of Al₁₃, preferably lessthan about 5% of Al₁₃, more preferably less than about 5% of Al₁₃.

In one embodiment, the activated aluminum sesquichlorohydrate (AASCH)powders in accordance with the present invention optionally contain abuffering agent. In other embodiments, the activated aluminumsesquichlorohydrate (AASCH) powders in accordance with the presentinvention do not contain any buffering agent.

DETAILED DESCRIPTION OF THE INVENTION

The invention will be described in more detail below.

While the specification concludes with the claims particularly pointingout and distinctly claiming the invention, it is believed that theinvention described herein will be better understood from the followingdescription. All temperatures are in degrees Celsius unless specifiedotherwise. The invention described herein can comprise (open ended) orconsist essentially of the components of the invention described hereinas well as other ingredients or elements described herein. As usedherein, “comprising” means the elements recited, or their equivalent instructure or function, plus any other element or elements which are notrecited. The terms “having,” “including,” and “comprised of” are also tobe construed as open ended unless the context suggests otherwise. Asused herein, “consisting essentially of” means that the invention mayinclude ingredients in addition to those recited in the claim, but onlyif the additional ingredients do not materially alter the basic andnovel characteristics of the claimed invention. Generally, suchadditives may not be present at all or only in trace amounts. However,it may be possible to include up to about 10% by weight of materialsthat could materially alter the basic and novel characteristics of theinvention as long as the utility of the compounds (as opposed to thedegree of utility) is maintained. All ranges recited herein include theendpoints, including those that recite a range “between” two values.Terms such as “about,” “generally,” “substantially,” and the like are tobe construed as modifying a term or value such that it is not anabsolute. Such terms will be defined by the circumstances and the termsthat they modify as those terms are understood by those of skill in theart. This includes, at very least, the degree of expected experimentalerror, technique error and instrument error for a given technique usedto measure a value.

It should be further understood that a description in range format ismerely for convenience and brevity and should not be construed as aninflexible limitation on the scope of the invention. Accordingly, thedescription of a range should be considered to have specificallydisclosed all the possible sub-ranges as well as individual numericalvalues within that range. For example, description of a range such asfrom 1 to 6 should be considered to have specifically disclosedsub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4,from 2 to 6, from 3 to 6 etc., as well as individual numbers within thatrange, for example, 1, 2, 2.3, 3, 4, 5, 5.7 and 6. This appliesregardless of the breadth of the range.

The term “concentration” used with respect to Band I, II, III, or IVpolymer is used interchangeably with the term “amount”. For example, acertain % of Band I polymer concentration is relative to the totalconcentration of Band I, II, III and IV. The concentration of Band I,Band II, Band III or Band IV polymers is analyzed by the size exclusionchromatogram (SEC) using a high performance liquid chromatograph (HPLC)as described hereinafter. A Phenomenex Column (3.9×300 mm, 10 umpacking) and a Waters column (μPorasil Column 3.9×300 mm, 10 um packing)were connected in series to obtain a SEC-HPLC chromatograph. The HPLCemployed is a Shimadzu RID 10A refractive index detector equipped withLC20 AD isocratic pump and 20 μL injector. For example, to measure theconcentration of a specific Band polymer in activated aluminumsesquichlorohydrate (AASCH) powders, they were dissolved in DI water toform a 2% by weight Al solution and quickly injected into the HPLC andeluted at a flow rate of 0.9 mL/min with mobile phase of 0.01N nitricacid.

The highest molecular weight Al polymer species are eluted firstdesignated as Band I. Band II and Band III are intermediate size Alcomplexes. Band IV is Al monomers and dimmers. The relative Band area ofone or more peak is determined in order to characterize the distributionof polymeric species (e.g., Band I, II, III and IV) in the aluminumcomplexes formed.

The term “particle size” used herein is meant to refer to the volumemean diameter of the particles. The volume mean diameter is determinedby laser light scattering using a Malvern-Mastersizer apparatus. Asample for analysis was prepared by adding a small amount of powder in acarrier medium. When the powder material is AASCH, isopropyl alcohol wasused as the carrier medium.

Method

In one embodiment, the present invention provides a method for producingactivated aluminum sesquichlorohydrate (AASCH) powders. In oneembodiment, the method comprises diluting a concentrated aluminumsesquichlorohydrate (ASCH) solution of at least about 40% by weight toform a diluted ASCH solution of about 1% to about 25% by weight,preferably about 5 to about 20% by weight, more preferably from about 5to about 15% by weight; heating the diluted ASCH solution to from about85° C. to about 105° C. for at least about 30 minute, preferably atleast about 60 minutes and most preferably at least about 90 minutes toform an activated aluminum sesquichlorohydrate (AASCH) solution; anddrying the AASCH solution to form activated aluminum sesquichlorohydrate(AASCH) powders, wherein the AASCH powders have Al:Cl atomic ratio offrom about 1.6 to about 1.9 and have a Band III polymer concentration ofat least 20% and a Band IV polymer concentration of at least 15%.

We found that it is more difficult to activate basic aluminumchlorohydrate when Al:Cl ratio is below 1.5, i.e. less Band III and moreacidic Al monomers will be formed. Further, upon drying the dilutedaluminum sesquichlorohydrate solution after the heat treatment when theAl:Cl ratio is under 1.6, more acid is produced during spray drying. Wefound the lower the Al:Cl ratio of the feed solution, the more the freeacid is produced. We also observed the AASCH powder having Al:Cl ratiobelow 1.6 contains lower Al content and more moisture, i.e. the lowerthe Al:Cl ratio the more the hygroscopic the AASCH powder becomes. Themore hygroscopic the AASCH powder, the more readily the powder absorbsthe moisture from the environment to form larger agglomerate, thuseasier to clog the orifice nozzle of aerosol can. By controlling Al:Clratio above 1.60, the AASCH powder will be less hygroscopic thussuitable for aerosol application. If the Al:Cl is more than 1.9, a BandIV polymer concentration is reduced to less than 10%, thus less Almonomers and dimers will be generated which would lead to lowerantiperspirant efficacy.

The method may further comprise a step of sieving or milling theactivated aluminum sesquichlorohydrate (AASCH) powders to obtainparticles having an particle size from about 1 micron to about 200microns, preferably from about 5 microns to about 150 microns and mostpreferably from about 10 microns to about 90 microns. Preferably, lessthan about 20% of the sieved or milled AASCH powders have a particlesize under about 10 microns and 100% of the sieved or milled AASCHpowders have particles size under about 120 microns.

In one embodiment, the diluted solution is heated to about 60° C. toabout 110° C., preferably about 85° C. to about 100° C., and morepreferably from about 90 to about 95° C. for from about 30 minutes to 5hours, preferably from about 1 hour to 4 hours.

In one embodiment, the concentrated aluminum sesquichlorohydrate (ASCH)is prepared directly in the reactor through the reaction of Al metalwith HCl or aluminum chloride. In another embodiment, the concentrationASCH is prepared by mixing 50% aluminum chlorohydrate (ACH) solutionwith HCl or basic polyaluminum chloride.

In one embodiment, the concentrated ASCH solution has Band I polymerconcentration of less than 5% and Band III polymer concentration of lessthan 20%, but more than 0%. In another embodiment, the concentrated ASCHsolution has Al:Cl atomic ratio of from about 1.5 to about 1.9. We foundthat it is more difficult to activate aluminum sesquichlorohydrate(ASCH) when Al:Cl ratio is below 1.5, i.e. less Band III and more acidicAl monomers will be formed. If the Al:Cl is more than 1.9, a Band IVpolymer concentration is reduced to less than 10%, thus less Al monomersand dimers will be generated which would lead to lower antiperspirantefficacy.

The diluting of the concentrated aluminum sesquichlorohydrate (ASCH)solution may be done by adding any suitable solvent including, but notlimited to water, propylene glycol, butylene glycol, 1,3-butane-diol,1,4-butane-diol, diethylene glycol, dipropylene glycol, tripropyleneglycol, glycerin, sorbitol, or mixtures thereof.

In comparison to the activation of ACH solution, the activation of ASCHsolution to form the AASCH takes less energy. Also, when the ASCHsolution is activated, the Al species in the AASCH are furtherdepolymerized demonstrated by high Band III and Band IV polymerconcentration and low or no Band I polymeric species concentrationcompared to those in AACH.

In one embodiment, no acid or acidic aluminum chloride is introduced tothe reaction solution after the heat treatment is completed. This isbecause either acid or aluminum chloride will produce free acid duringthe drying step, such as spraying drying, and may cause corrosion of theprocess equipment, such as spray dryer and milling equipment. Furtherthe presence of the free acid in the drying and milling system willcause agglomeration of the dried activated powders. The combination ofthe corrosion of spray dryer and agglomeration of the dried activatedpowders will generate large colored specks such as black, brown, greenand yellow colors.

In some embodiments, a buffering agent is introduced to the activatedAASCH solution prior to the drying step. Suitable buffering agentsinclude, without limitation, amino acids such as glycine, betaine, urea,alkaline and alkaline earth glycinate, zinc glycinate, calciumglycinate, strontium glycinate, and mixtures thereof. Examples ofalkaline glycinate include, without limitation, lithium, sodium,potassium, ribudium, caesium and francium glycinates. Examples ofalkaline earth glycinate include, without limitation, beryllium,magnesium, calcium, strontium, barium and radium. In some embodiments,the amount of a buffering agent present in the activated aluminumsesquichlorohydrate (AASCH) powder is from about 0.5% to about 10%,preferably from about 1% to about 5%.

The feed solution of the activated Al sesquichlorohydrate (AASCH) ispreferably spray dried to a powder. The powder can be in the form of aparticle. Most preferably most of the AASCH powders are sphericalparticles.

In order to be suitable for aerosol application, the powder ispreferably to have less than 20% under 10 microns and 100% under 120microns. In one embodiment, the pH of the AASCH powders range from about3.0 to about 4.5, more preferably from about 3.5 to about 4.2. The pH ismeasured by dissolving the AASCH powders in D.I. water to form a 15% byweight solution.

AASCH Powders

In one embodiment, the present invention provides activated aluminumsesquichlorohydrate (AASCH) powders for aerosol application that hasenhanced antiperspirant efficacy, leaves low or no white residue anddoes not corrode the aerosol can. In another embodiment, the AASCHpowders have an Al:Cl atomic ratio of from about 1.60 to about 1.90 andhave a Band III polymer concentration of at least about 20% and a BandIV polymer concentration of at least about 15%. Preferably, the atomicratio of Al:Cl is from about 1.65 to about 1.85 and most preferably fromabout 1.70 to about 1.80.

The activated aluminum sesquichlorohydrate (AASCH) powders preparedaccording to the present invention comprise at least about 20%, andpreferably at least about 30% and most preferably at least about 40% ofBand III polymer. In one embodiment, the AASCH powders have a Band IIIpolymer concentration of from about 20% to about 70%, preferably fromabout 20% to about 60%.

Moreover, the AASCH powders in accordance with the present inventionhave at least about 15%, preferably at least about 20%, and mostpreferably at least about 30% of Band IV polymer. In another embodiment,the AASH has a Band IV polymer concentration of from about 15% to about50%, preferably from about 15% to about 40%.

Preferably, the AASCH powders in accordance with the present inventionhave less than about 1% Band I, more preferably no Band I polymers atall.

In yet another embodiment, the activated aluminum sesquichlorohydrate(AASCH) powders in accordance with the present invention have an Alspecies distribution that includes at least about 5% of Al₃₀, andpreferably at least about 10% of Al₃₀. In another embodiment, theactivated aluminum sesquichlorohydrate (AASCH) powder in accordance withthe present invention has an Al species distribution that includes lessthan 10 of Al₁₃, and preferably less than about 5% of Al₁₃.

In yet another embodiment, the activated aluminum sesquichlorohydrate(AASCH) powders in accordance with the present invention have themoisture content of about 2% to about 15%, and preferably from about 3%to about 8%. The moisture content is measured by Infrared moisturebalance (Mettler Toledo, model HB43). About 3 grams of the AASCH powderswere employed for the moisture content measurement.

The activated aluminum sesquichlorohydrate (AASCH) produced by themethod in accordance with the present invention has Al:Cl atomic ratioof from about 1.60 to about 1.90, preferably from about 1.65 to about1.85 and most preferably from about 1.70 to about 1.80.

In one embodiment, the AASCH powder according to present invention hasless white residue in comparison with AACH. Not wishing to be bound withtheory, it is believed that the presence of more depolymerized Alspecies in AASCH will minimize the scattering of the light by thepowder, thereby rendering the active less visible to the naked eye.

In some embodiments, a buffering agent may be included in the AASCHpowder. Suitable buffering agents include, without limitation, aminoacids such as glycine, betaine, urea, alkaline and alkaline earthglycinate, zinc glycinate, calcium glycinate, strontium glycinate andmixtures thereof. We found addition of glycine does not have much effecton Band III. Band IV, however is reduced. The same effect has beenobserved with zinc glycinate. In some embodiments, the amount of abuffering agent present in the activated aluminum sesquichlorohydrate(AASCH) powder is from about 0.5% to about 10%, preferably from about 1%to about 5%.

In other embodiments, the AASCH powder in accordance with the presentinvention does not contain any buffering agent, such as glycine. In yetanother embodiment, the AASCH powder in accordance with the presentinvention is substantially free of zirconium.

In order to be suitable for aerosol application, the powder ispreferably to have less than 20% under 10 microns and 100% under 120microns. In one embodiment, the pH of the AASCH powders range from about3.0 to about 4.5, more preferably from about 3.5 to about 4.2. The pH ismeasured by dissolving the AASCH powders in D.I. water to form a 15% byweight solution.

EXAMPLES

The following Examples illustrate some embodiments of the presentinvention. In the Examples, % Al and % Cl are by weight. % Band I, %Band III and % Band IV are peak areas, wherein % Band I+% Band II+% BandIII+% Band IV=100%. Both 50% ACH and concentrated ASCH solutions arecommercial solutions and manufactured by Gulbrandsen Technologies.

Example 1

50% aluminum chlorohydrate (ACH) solutions were mixed with basicpolyaluminum chloride solutions to form a concentrated aluminumsesquichlorohydrate (ASCH) solution having various Al:Cl ratios rangingfrom 1.5 to 1.8. Then, water was added to dilute the concentratedaluminum sesquichlorohydrate (ASCH) solutions to 4.1% Al to 4.3% Al byweight, which corresponds to about 16.5% to about 17.4% by weight. Thediluted solution is heated to about 90° C. to about 95° C. for about 2hours to form an activated aluminum sesquichlorohydrate (AASH). Thesolutions were spray dried to powders. Table I below lists thecharacteristics of the resulting activated aluminum sesquichlorohydrate(AASH) powders.

TABLE I Al:Cl % Band % Band % Band % Al % Cl Ratio % M/C* I III IV 23.0518.98 1.60 10.11 0.00 23.46 31.29 24.10 18.78 1.69 8.92 0.00 27.35 29.1924.04 18.29 1.73 8.57 0.81 32.18 15.34 24.09 18.07 1.75 8.14 0.93 34.4019.36 24.71 17.83 1.82 7.12 0.97 36.44 14.64 *moisture content

Example 2

In Example 2, % Al concentrations of the feed solution were about 3.5%Al, which corresponds to 14% by weight, and the feed solution hadvarious Al:Cl ratios ranging from 1.5 to 1.8. This set of experiment isdirected to study the effect of concentration of the feed solutions onthe SEC-HPLC Band profile. By comparing the results of Example 1 toExample 2, we found by decreasing the concentration of the feedsolutions to 3.5% Al, Band III and Band IV peak areas are increased andBand I peak area is decreased as shown in Table II.

TABLE II Al:Cl % Band % Band % Band % Al % Cl Ratio % M/C I III IV 23.4419.95 1.54 11.62 0 35.55 41.32 23.9 17.92 1.75 9.09 0 41.77 37.75 24.717.35 1.87 7.96 0 40.77 33.74

Example 3

Different amount of glycine were added to the diluted and heated AASCHsolutions and the solutions were spray dried. One of the case, glycinewas not added. Compared with the AASCH powders with no glycine, theAASCH powders with glycine showed reduced Band IV peak area.

TABLE III Al:Cl % % Band % Band % Band % Al % Cl Ratio Glycine % M/C IIII IV 23.35* 17.90 1.71 3.9 9.12 0 53.58 20.73 23.12 17.60 1.73 3.99.12 0 41.28 20.61 23.69 17.93 1.74 0 8.76 0 41.63 30.23 23.69 17.931.73 4 8.17 0 39.24 25.35 The concentration of the feed solution is 3.5%Al while the rest of the solution has 3.9% Al

Example 4

Different amounts of zinc glycinate were added to the concentrated ASCHsolution, followed by dilution and heat treatment. The resultantsolutions were spray dried to powders and the results are demonstratedin Table IV.

TABLE IV Al:Cl % % Band % Band % Band % Al % Cl Ratio Glycine % Zn I IIIIV 23.25 17.75 1.72 2.85 0.70 0.23 36.36 20.11 23.68 18.00 1.73 4.781.16 0.32 37.36 20.56 23.29 17.81 1.72 6.67 1.61 0.92 36.41 20.41

Example 5

The scale ups at both pilot plant and large-scale production levels wereconducted. For the pilot plant process, 8.25 Kg of ASCH solution wasdiluted with 22 Kg of water and the solution was heated until Band IIIwas above 50%. The feed solution was then spray dried in pilot plantspray dryer at 250° C. inlet and 130° C. outlet temperatures to form thefree flowing white powder.

For the production-scale process, 7766 Kg of ASCH solution and 19,000 Kgof water were mixed and heated until Band IV was higher than 50%. Thesolution was spray dried at 280° C. inlet and 130° C. outlettemperatures to the powder.

TABLE V Al:Cl % Band % Band % Band % Al % Cl Ratio I III IV pilot run24.14 18.35 1.73 0 49.61 22.00 Production- 25.12 18.31 1.80 0 49.9219.69 scale

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

I claim:
 1. Aluminum sesquichlorohydrate (AASCH) powders prepared by:(a) diluting a concentrated aluminum sesquichlorohydrate (ASCH) solutionto about 1% to about 25% by weight, (b) heating the diluted solution toactivate the solution, and (c) drying the activated solution to form theactivated aluminum sesquichlorohydrate (AASCH) powders, wherein theactivated AASCH powders have an Al:Cl ratio of from about 1.60 to about1.90, and wherein the activated AASCH powders have a Band III polymerconcentration of at least 20% and a Band IV polymer concentration of atleast 15%, and wherein no acid or acidic aluminum chloride is introducedafter the heating of the diluted solution.
 2. Aluminumsesquichlorohydrate (AASCH) powders of claim 1, wherein the Band IIIpolymer concentration is at least 40% and the Band IV polymerconcentration is at least 20%.
 3. Aluminum sesquichlorohydrate (AASCH)powders claim 1, further comprising adding a buffering agent prior tothe drying to form the powder.
 4. Aluminum sesquichlorohydrate (AASCH)powders of claim 3, wherein the buffering agent is selected from thegroup consisting of amino acid, alkaline glycinate, alkaline earthglycinate, zinc glycinate, strontium glycinate, and mixtures thereof. 5.Aluminum sesquichlorohydrate (AASCH) powders of claim 3, wherein thebuffering agent is selected from the group consisting of glycine,betaine, urea and mixtures thereof.
 6. Aluminum sesquichlorohydrate(AASCH) powders of claim 1, wherein the diluted solution is heated toabout 85° C. to about 105° C. for at least 30 minutes.
 7. Aluminumsesquichlorohydrate (AASCH) powders of claim 1, wherein the diluting ofthe concentrated sesquichlorohydrate (ASCH) solution includes adding asolvent.
 8. Aluminum sesquichlorohydrate (AASCH) powders of claim 1,wherein the concentrated ASCH solution has a Band I polymerconcentration of less than 5% and Band III polymer concentration of atleast 20%.
 9. Aluminum sesquichlorohydrate (AASCH) powders of claim 1,wherein the concentrated ASCH solution has an Al:Cl ratio ranging fromabout 1.5 to about 1.9.
 10. Aluminum sesquichlorohydrate (AASCH) powdersof claim 1, further comprising sieving or milling the AASCH powders. 11.Aluminum sesquichlorohydrate (AASCH) powders of claim 10, wherein thesieved or milled AASCH powders have a particle size ranging from about 1micron to about 200 microns.
 12. Aluminum sesquichlorohydrate (AASCH)powders of claim 1, wherein Band I polymer concentration is less than1%.
 13. Aluminum sesquichlorohydrate (AASCH) powders of claim 1, whereinthe AASCH powders are substantially free of zirconium.
 14. Aluminumsesquichlorohydrate (AASCH) powders of claim 1, wherein the drying isspray drying.
 15. Aluminum sesquichlorohydrate (AASCH) powders of claim1, wherein the AASCH powders have at least 5% of Al₃₀.
 16. Aluminumsesquichlorohydrate (AASCH) powders of claim 1, wherein the AASCHpowders have less than 10% of Al₁₃.
 17. Aluminum sesquichlorohydrate(AASCH) powders of claim 1, wherein the AASCH powders have a moisturecontent ratio ranging from about 2% to about 15%.
 18. Aluminumsesquichlorohydrate (AASCH) powders of claim 1, wherein the AASCHpowders have a pH ranging from about 3.0 to about 4.5.
 19. Anantiperspirant formulation comprising the aluminum sesquichlorohydrate(AASCH) powders of claim 1.